Shells and algae such as barnacles, oysters, mussels, hydroids, tube worms, bryozoans, tunicares, bryozoans (Ex. Bugula), sea weeds (Ex. Ulva), sea weeds (Ex. Enteromorpha), sea weeds (Ex. Ectocarpus) and the like settle to and propagate on ship hills, in-sea-water facilities (e.g. buoys), in-water structures (e.g. part of dam facilities), feed pipes of cooling water for condenser used in steam power plant or for heat exchanger used in petrochemical plant, etc. (these parts and facilities are in constant contact with water), fishing nets for cultivation or for fixed net fishing, etc., when these parts, facilities and materials have not been subjected to any treatment. These fouling organisms invite increased resistance of water supply and reduced thermal conductivity, and bring about disadvantages such as reduced function of facility and the like. In fishing nets, the settlement of the above-mentioned organisms causes stopping-up of meshes and resultant oxygen shortage, scratching of fish (this reduces the commercial value of fish), and infection of fish with diseases caused by microbes, etc. In order to prevent the settlement and propagation of such sea-water or pure-water fouling organisms, antifouling agents containing an organotin compound as an effective ingredient have been used heretofore. With antifouling agents containing an organotin compound or the like, however, there have recently arisen social problems that environments such as rivers, ocean and the like are polluted and further that said agents give harm to human bodies via fish. Hence, a regulation has been established on the use of organotin compounds, and the use and production of said organotin compounds are under mandatory control.
Meanwhile, organic compounds other than organotin compounds have been studied as an antifouling agent for the same purpose. However, preventive agents for fouling organisms, containing conventional organic compounds have not been satisfactory in antifouling property.
It is an object of the present invention to solve the above-mentioned problems and provide a preventive agent for fouling organisms, containing, as an effective ingredient, an organic compound other than organotin compounds, having high safety and exhibiting a high antifouling effect at a low dosage.
In order to achieve the above object, the present inventors made a study on the preventive activities of various organic compounds for fouling organisms. As a result, the present inventors unexpectedly found out that some of 3-oxopropionitrile derivatives have high preventive activities for fouling organisms and that the use of said compound can achieve the above object and can provide a preventive agent for fouling organisms, having a high antifouling effect. The present invention has been completed based on these findings.